Drop foot is characterized by an insufficient control to check plantarflexion, inversion and/or eversion of the foot while walking. Consequentially, a victim suffering from drop foot walks with the toe of an affected foot dragging along the ground. Further, the affected foot may twist inversionally or eversionally. Either or both symptoms provide a sufferer of drop foot with an embarrassing and unsafe gait. Generally, drop foot is incurred by stroke victims, multiple sclerosis patients and/or those suffering from neurological, muscular and/or orthopedic pathological conditions. Victims of any of these pathological conditions can be especially prone to medical complications which may result from a fall caused by tripping due to the drop foot stride.
Drop-foot and similar pathological conditions can be corrected utilizing an appropriate ankle-foot orthosis. Moreover, in many cases, by utilizing an appropriate ankle-foot orthosis in a therapeutic rehabilitation program, the patient can be cured of at least the symptomatic gait associated with drop-foot.
It is advantageous for a therapeutic rehabilitation program to include the patient's normal daily routine, such as walking while involved in working or social situations. In this case, the ankle-foot orthosis should not only be effective in (Correcting foot drop, but also comfortable to wear and not overly conspicuous so as not to draw attention to the infirmity or otherwise embarrass the patient. Further, an appropriate drop-foot orthosis should be relatively inexpensive, not requiring the patient to acquire different sets of shoes (which can be used only during rehabilitation due to differing sizes), and adaptable to a wide variety of shoe styles. Still further, the ankle-foot orthosis should be adjustable to be applicable to a wide variety of orthopedic needs and rehabilitation stages. In light of the circumstance that many drop-foot patients suffer from pathological conditions also affecting their dexterity, the ankle-foot orthosis should also be simple to use.
Before the present invention, there has been no ankle-foot orthosis design that successfully and fully addresses these concerns. Many attempted to provide a static stop to prevent any plantarflexion, such as Mason et al.'s U.S. Pat. No. 4,289,122 and Goffredo's U.S. Pat. No. 2,584,010, but these devices have proved, in many cases, to aggravate the patient's condition since the muscles used for plantarflexion tend to atrophy from disuse. Mason et al., as well as other devices, such as Shad's U.S. Pat. No. 3,986,501, require a larger than normal-size shoe to accommodate the brace, and necessitate the leg's intimate and extensive contact with the brace which increases the user's discomfort. Further, in Goffredo and Shad, methods of applying the orthosis to the foot challenge a patient's dexterity. Furthermore, these devices, like those of Heaney's U.S. Pat. No. 4,329,982 and Deis' U.S. Pat. No. 4,566,447, do not address lateral (laterally outward) or medial-lateral (laterally inward) support of the foot. Although lateral support is addressed in Wertz's U.S. Pat. No. 4,817,589, Wertz discloses a lever arm which is too short for either effectively encouraging dorsiflexion or discouraging plantarflexion. Also, Wertz's support member is unstably secured to the leg and may slip from its relative position due to the movement of the foot, destroying the brace's potential effectiveness, since it is merely held firm to the back of the leg via the elastic straps. Furthermore, none of these orthosises provides for ease in adjustability of their supports. Von Baeyer's drop foot brace, as illustrated on page 426, FIG. 700 of the Orthopaedic Appliances Atlas, Volume I (1952), although providing sufficient moment arm and ease of adjustability for its elastic supports, which encourage the dorsiflexion of the foot and control the lateral or medial-lateral deflection of the foot, appears to provide for intimate contact of the foot with the straps by securing the straps inside the shoe, and further appears to provide at least one static stop for plantarflexional motion.